Looking into any heating system, all manufacturers tie their warranty into a maintenance schedule. After one year most manufactures want the heat exchanger to be internally inspected to ensure that there is proper combustion and that there is not excessive buildup on the inside (see picture).
Once the first inspection has taken place we are then able to establish a maintenance schedule that suits the wear and tear on the boiler. Maintenance intervals can range from 8 months to several years. On top of the heat exchanger cleaning, the most important aspect of high-efficiency boiler maintenance is the pH of the water and ensuring that it remains within the manufacturer's specified range. Too high, or too low can result in premature Heat Exchanger failure from the inside - and this is typically NOT covered under warranty unless the correct pH has been maintained (typically 7-9pH).